Modeling of runaway inhibition in batch reactors using encapsulated phase change materials

Abstract

Thermal runaway is a common hazard leading to process safety-related accidents. Uncontrolled release of chemical energy poses extreme risks for batch reactors. In this study, we fabricated encapsulated phase change materials (PCMs) with silica shells as inhibitors to improve the thermal management of reactors and mitigate reaction thermal runaway. The prepared encapsulated PCMs had core-shell microstructures and spherical morphologies, with an average particle diameter of 980 nm and a silica shell thickness of 100 nm. A series of inhibition experiments were conducted with 0.5 and 1 g of encapsulated PCMs. Three stages were identified from the inhibition experiments. Kinetic parameters of esterification of propionic anhydride with 2-butanol, catalyzed by sulfuric acid, were estimated based on an autocatalytic parallel reaction model. An inhibition effect-kinetic model was proposed to simulate the inhibition process of the thermal runaway reaction. The results revealed that thermal storage and heat transfer intensification of encapsulated PCMs play a crucial role in the inhibition process. The effect of stirring rate, dispersity of encapsulated PCMs, and warning temperature of thermal runaway while optimizing the injection strategy of inhibitors was assessed. The inhibition of thermal runaway under adiabatic conditions was relatively low.